How long is the circumference of the Earth? What is the circumference of the Earth?

The radius of the equator is slightly longer, the radius of the poles is slightly shorter, and the polar axis is equivalent to the axis of rotation of an oblate sphere. According to the main data on the shape and size of the Earth published by the International Union of Geodesy and Geophysics in 1980, the following are as follows: Equatorial Radius Polar Radius Average Radius Flattening Ratio 1 Equatorial Circumference Meridian Circumference Surface Area Volume 10832 108km3 In fact, the true shape of the Earth is slightly different from the above-mentioned oblate sphere.

Its southern hemisphere is slightly thicker and shorter, and the antarctic is concave inward about 30m; The Northern Hemisphere is slightly slender and long, with the North Pole protruding about 10 m upward. So it is an exaggeration to say that the true shape of the earth is slightly pear-shaped.

Suppose the Earth is a sphere, and the total of the central angles of the circle is 360 degrees. So if two cities are 7 degrees apart, then the distance between them should be 7 360 for the full circumference, which is about 1 50. Elotosinus estimated that the distance between the two places was 5,000 stadias, and that the total length of the earth's circle should be 50 times the distance between the two places, or 250,000 stadias.

Scholars still dispute the exact length of Greek Stardia, so it is impossible to know how accurate Elotosinus's conclusions were, but he was only five percent wrong.

Eratosthenes, the first to calculate the circumference of the Earth More than 2,000 years ago, someone used a simple measuring tool to calculate the circumference of the Earth. This man was Eratosthenes of ancient Greece (c. 275-194 BC). Eratosthenes was a man of great learning, not only astronomy but also geography; He was also a poet, historian, linguist, philosopher, and former director of the Alexandria Museum.

The observant Eratosthenes found that in the city of Seon (near present-day Aswan, Egypt), about 800 kilometers from Alexandria, the summer midday sun could reach the bottom of the well, so that all the upright objects on the ground should have no shadows at this time. However, there is a short shadow of the upright on the ground in Alexandria.

He believed that the shadow of the erectus was caused by the angle between the sunlight of Alexandria and the erectus. Starting from the premise that the earth is a sphere and sunlight travels in a straight line, two straight lines are drawn from the imaginary center of the earth to the cities of Seon and Alexandria, where the angle should be equal to the angle formed by the sunlight of Alexandria and the upright.

According to the proportions of similar triangles, the distance between two places can be determined, and the circumference of the earth can be measured. Eratosthenes measured an angle of about 7 degrees, which is one-fiftieth of the circumference of the Earth (360 degrees), and estimated that the circumference of the Earth is about 40,000 kilometers, which is not much different from the actual circumference of the Earth (40,076 kilometers). He also calculated that the distance between the sun and the earth is 100 million kilometers, which is surprisingly close to the actual distance of 100 million kilometers.

This fully reflects the doctrine and wisdom of Eratosthenes. Eratosthenes was the first to use the name "geography", and since then he has written a three-volume treatise instead of the traditional "local chronicles". The shape, size, and distribution of land and sea are described.

Eratosthenes also used graticules to draw maps, and was the first to combine the principles of physics with mathematical methods to create mathematical geography. Resources.

The circumference of the Earth's equator is about 40,076 kilometers.

Earth is one of the eight planets in the solar system, the third planet in order from near to far, and it is also the terrestrial planet with the largest diameter, mass and density in the solar system, 100 million kilometers away from the sun. The Earth rotates from west to east while revolving around the Sun. It is 4,04.6 billion years old, and it has a natural satellite, the Moon, which forms a celestial system, the Earth-Moon System.

It originated from the primordial solar nebula 4.6 billion years ago.

The radius of the Earth's equator is kilometers, the polar radius is kilometers, and the average radius is about 6371 kilometers. The surface area of the earth is 100 million square kilometers, of which 71% is oceans and 29% is land.

Earth Data

Age: 4.6 billion years.

Revolution period: about 365 days.

Return Year Length:

Sky. Orbit: elliptical in shape. Ahelion is in early July and perihelion in early January.

Rotation period: sidereal day: about 23 hours 56 minutes. Solar day: 24 hours.

Rotation direction: from west to east.

Yellow-equatorial angle: The angle of intersection of the ecliptic plane and the equatorial plane:

Polar radius: The distance from the center of the earth to the north or south pole, about 3,950 miles (km) (the difference between the poles is negligible).

Equatorial radius: The distance from the center of the earth to the equator, about 3,963 miles (kilometers).

Average radius: Approximately 3959 miles (

km). This number is the average of the distance from the center of the earth to all points on the earth's surface. Volume: 1,083.2 billion cubic kilometers.

Mass: tons. Average density:

g/cm^3

Earth's surface area: 100 million square kilometers.

The ocean covers an area of 100 million square kilometers.

Atmosphere: Main components: nitrogen (and oxygen) (.

Earth's crust: main components: oxygen (47%), silicon (28%) and aluminium (8%).

Surface atmospheric pressure:

mPa, or 760 mm high Hg.

Satellite (natural): 1 (Moon).

Floor area: ra=6378137

39,250 km In the 3rd century B.C., there was an ancient Greek mathematician named Eratosphine. He was of great intellect and versatility, and was also highly accomplished in the fields of astronomy, geography, mechanics, history, and philosophy, and was even a good poet and an excellent athlete. Eratosfinn was recognized as a rare prodigy, praised him for his important contributions in all fields of knowledge at the time, but believed that he was not the most outstanding in any field and was always in second place, so he was given the nickname'Beta"。

It means number two. I can get it"Beta"'s nickname is not easy, because Archimedes, the greatest genius of antiquity, lived in the same era as Eratosfin! The two of them are close friends, and they often correspond to exchange research results and discuss how to solve problems.

As you know, Archimedes solved it"The problem of sand grains", calculate how many grains of sand are needed to fill the cosmic space, which makes people jaw-dropping. Presumably under the influence of Archimedes, Eratosphine also answered a daunting question: how big is the Earth?

How do you determine the size of the earth? Eratosphine came up with an ingenious idea: to measure the circumference of the Earth.

Eratosphine lives in Alexandria, 785 kilometers directly south of the city, in another city called Seni. There is a very interesting phenomenon in the city of Seni, every year at 12 noon on the day of the summer solstice, the sun can directly hit the bottom of a dry well in the city, that is, at noon on the day of the summer solstice, the sun hangs exactly on the zenith of the city of Seni. Alexandria and Seigne are almost on the same meridian.

At the same time, there was no such sight in Alexandria. The sun is slightly away from the zenith. At noon on a summer solstice, Eratosphine erected a small stick in the city and measured the angle between the direction of the zenith and the sun's rays, and measured that the angle was equal to 1 50 of 360o.

Since the Sun is so far away from the Earth, sunlight can be approximated as rays of light parallel to each other. Thus, according to the theorem about parallel lines, Eratosfen came to the conclusion that 1 is equal to 2. In geometry, an angle like 2 is called a central angle.

According to the theorem of the central angle, the degree of the central angle is equal to the degree of the arc to which it is opposed. Since 2 = 1, and its degree is also 1 50 of 360o, the length of the arc representing the distance between Alexandria and Seni should be equal to 1 50 of the circumference of the circumference. Other words.

The actual distance between Alexandria and Seni is exactly 1 50 of the Earth's circumference. So, according to the actual distance between Alexandria and Seni, multiply by 50 to calculate the circumference of the earth. Eratosphene's calculations are:

The circumference of the Earth is 39,250 km. This is the first time in human history that such a measurement has been made. Remembering that 1800 years after Eratosfin's death, there were still people babbling about whether the earth was round or square, and Eratosfin's superb computing power and amazing courage were all the more praised.

The circumference of the Earth's equator is about kilometers.

The circumference of the equator is long, and the blood vessels can be connected three times.

Earth: Semi-major diameter 149,597,887 km ( 000 11 AU) orbital circumference trillion meters ( AU) orbital eccentricity 710 22 perihelion 147,098,074 km ( 289 9 AU) aphelion 152,097,701 km ( 710 3 AU) sidereal orbital period 96 days ( 019 1 Julian year) Conjunction period No data Average orbital velocity km s Maximum orbital velocity km seconds Minimum orbital velocity km seconds Orbital ecliptic tilt 05° (with the equator of the Sun Ascending node longitude 36° perihelion amplitude 83° 1 satellite (Moon), see also asteroid 3753 Physical Properties Equatorial diameter 12, km Pole diameter 12, km Average Earth diameter 12, km Flattening rate 35 Equatorial circumference 40, km Polar circumference 39, km Surface area 510,067,420 sq km Volume cubic km Mass kg Density g cubic centimeter Equatorial surface gravity meters per second square [1] (32 gravitational constants) Escape velocity km seconds sidereal rotation period 258 days ( hours) rotation speed km hours = m seconds.

The circumference of the Earth is 40,075 km. The Earth's equatorial radius is kilometers, the polar radius is kilometers, the average radius is about 6371 kilometers, and the equatorial circumference is about 40076 kilometers. There is the Earth's core, mantle, and crustal structure inside, and the Earth's outer body has a hydrosphere, atmosphere, and magnetic field.

The surface area of the earth is 100 million square kilometers, of which 71% is oceans and 29% is land. The Earth rotates from west to east while orbiting the Sun.

Morphological characteristics of the Earth:The shape of the Earth is roughly ellipsoidal. The effect of the Earth's rotation is slightly flattened along the Earth's axis through the poles and slightly uplifted near the equator.

From the center of the earth, the radius of the Earth's equator is 43 kilometers (27 miles) higher than the polar radius. Thus, the farthest point on the Earth's surface from the Earth's center of mass is not Mount Everest, the highest elevation, but the summit of Mount Chimborazo in Ecuador, located on the equator. The Earth's reference spheroid has an average diameter of about 12,742 km (7,918 mi), which is approximately equal to (40,000 km).

The above content reference: Encyclopedia - Earth.

The circumference of the Earth is: about 40,075 km.

The radius of the Earth's equator is kilometers, the polar radius is kilometers, the average radius is about 6371 kilometers, and the equatorial circumference is about 40075 kilometers.

The Earth's surface area is 100 million square kilometers, of which 71% is oceans and 29% is land. The main components of the atmosphere are nitrogen and oxygen, as well as small amounts of carbon dioxide and argon.

Formation of the Earth:

The Earth was formed about 4.5 billion years ago, and this rocky planet was originally just dust floating in space from the size of a huge, ancient star at the end of its life.

The earth can also be divided into 5 since its formation"generations", from ancient to modern are: Archean, Proterozoic, Paleozoic, Mesozoic, and Cenozoic. Some generations are further divided into several"Discipline", such as the Paleozoic era from far to near divided into Cambrian, Ordovician, Silurian, Devonian, Carboniferous and Permian.

This is the roughest division of the period of the earth's history, called"Geological time"People in different geological ages have different characteristics.

In the Archean 2.4 billion years ago, primitive lithosphere, hydrosphere and atmosphere had formed on the surface of the earth.

The circumference of the Earth is 40,076 km.

Because the earth is not a sphere but an ellipse, so there are many places in circumference, and the circumference is measured according to modern means, and the exact value of the circumference at the equator of the earth is 40,076 kilometers. The circumference of the North and South Poles is 39,900 kilometers of the Earth's diameter, the average diameter of the Earth is 1,000 kilometers, and the diameter of the Earth's equator is 12,756 kilometers.

The diameter between the Earth's north and south poles is 12630824 meters, or about 12,631 kilometers. The average radius of the Earth is about 6,371 kilometers, and it is an irregular elliptical sphere with slightly flattened poles and slightly bulging equators. There is the Earth's core, mantle, and crustal structure inside, and the Earth's outer body has a hydrosphere, atmosphere, and magnetic field.

Introduction to Earth's contents:

Earth is one of the eight planets in the solar system, the third planet in order from near to far from the sun, and it is also the terrestrial planet with the largest diameter, mass and density in the solar system, 100 million kilometers away from the sun. The Earth rotates from west to east while revolving around the Sun. Existing between 40 and 4.6 billion years old, it has a natural satellite, the Moon, which makes up a celestial system, the Earth-Moon system.

It originated from the primordial solar nebula 4.6 billion years ago. The surface area of the earth is 100 million square kilometers, of which 71 percent is oceans and 29 percent is land. The Earth rotates from west to east while revolving around the Sun.

The Earth is the only celestial body in the universe where life is known to exist, and it is home to millions of living beings, including humans.